1816
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 16
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 3420
- Proper Divisor Sum (Aliquot Sum)
- 1604
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 904
- Möbius Function
- 0
- Radical
- 454
- Omega Function (Ω)
- 4
- Little Omega Function (ω)
- 2
Special
- Factorial
- no
- Catalan Number
- no
- Bell Number
- no
- Motzkin Number
- no
- Primorial
- no
Figurate Numbers
- Fibonacci Number
- no
- Triangular Number
- no
- Perfect Square
- no
- Perfect Cube
- no
- Pentagonal Number
- no
- Hexagonal Number
- no
- Lucas Number
- no
- Tetrahedral Number
- no
- Pell Number
- no
- Tribonacci Number
- no
- Pronic Number
- no
Recreational
- Happy Number
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 16
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- Prime Power
- no
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- yes
- Odd
- no
Appears in sequences
- Expansion of Product_{m >= 1} (1 + x^m); number of partitions of n into distinct parts; number of partitions of n into odd parts.at n=44A000009
- a(n) = 2^n - C(n,0) - C(n,1) - C(n,2) - C(n,3).at n=11A002663
- Generalized Euler numbers of type 2^n.at n=5A005799
- Number of partitions of n with at least 1 odd and 1 even part.at n=25A006477
- Coordination sequence T3 for Zeolite Code MEI.at n=31A008148
- Coordination sequence T2 for Zeolite Code STI.at n=29A008235
- Poupard's triangle: triangle of numbers arising in enumeration of binary trees.at n=20A008301
- a(n) = Sum_{k=0..7} binomial(n,k).at n=11A008860
- Triangle read by rows of partial sums of binomial coefficients: T(n,k) = Sum_{i=0..k} binomial(n,i) (0 <= k <= n); also dimensions of Reed-Muller codes.at n=73A008949
- Expansion of e.g.f. sinh(sinh(x))*exp(x).at n=8A009598
- Expansion of e.g.f. sinh(x)*exp(sinh(x)).at n=8A009623
- Coordination sequence T1 for Zeolite Code -ROG.at n=32A009859
- Coordination sequence T7 for Zeolite Code CON.at n=30A009874
- Coordination sequence T5 for Zeolite Code VET.at n=25A009906
- Coordination sequence T2 for Zeolite Code VNI.at n=26A009908
- Number of partitions of 1/n into 4 reciprocals of positive integers.at n=5A020327
- Numbers k such that the continued fraction for sqrt(k) has period 38.at n=11A020377
- a(n) = a(n-1) + a(n-2) + 1, with a(0) = 0 and a(1) = 11.at n=12A022316
- Place where n-th 1 occurs in A007337.at n=45A022777
- Numbers k such that Fib(k) == -21 (mod k).at n=20A023168